I am having a similar problem. I have had to make a clean install of Windows 10. I have the license key for LR5.4 which I have re-installed. I am now not able to update to 5.7.1. Each time I click on "Check for Updates", I land on the "Free Trail" page. How to do I get the update file? Help is much appreciated. Thank you.

I have clicked on the first link in the original post by "kglad" but that link also brings me to the "Free Trail" page. Look forward to hearing from anyone who might be able to help with the update file. Thank you.